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Henning RW, Kosheleva I, Šrajer V, Kim IS, Zoellner E, Ranganathan R. BioCARS: Synchrotron facility for probing structural dynamics of biological macromolecules. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2024; 11:014301. [PMID: 38304444 PMCID: PMC10834067 DOI: 10.1063/4.0000238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 01/10/2024] [Indexed: 02/03/2024]
Abstract
A major goal in biomedical science is to move beyond static images of proteins and other biological macromolecules to the internal dynamics underlying their function. This level of study is necessary to understand how these molecules work and to engineer new functions and modulators of function. Stemming from a visionary commitment to this problem by Keith Moffat decades ago, a community of structural biologists has now enabled a set of x-ray scattering technologies for observing intramolecular dynamics in biological macromolecules at atomic resolution and over the broad range of timescales over which motions are functionally relevant. Many of these techniques are provided by BioCARS, a cutting-edge synchrotron radiation facility built under Moffat leadership and located at the Advanced Photon Source at Argonne National Laboratory. BioCARS enables experimental studies of molecular dynamics with time resolutions spanning from 100 ps to seconds and provides both time-resolved x-ray crystallography and small- and wide-angle x-ray scattering. Structural changes can be initiated by several methods-UV/Vis pumping with tunable picosecond and nanosecond laser pulses, substrate diffusion, and global perturbations, such as electric field and temperature jumps. Studies of dynamics typically involve subtle perturbations to molecular structures, requiring specialized computational techniques for data processing and interpretation. In this review, we present the challenges in experimental macromolecular dynamics and describe the current state of experimental capabilities at this facility. As Moffat imagined years ago, BioCARS is now positioned to catalyze the scientific community to make fundamental advances in understanding proteins and other complex biological macromolecules.
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Affiliation(s)
- Robert W. Henning
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA
| | - Irina Kosheleva
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA
| | - Vukica Šrajer
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA
| | - In-Sik Kim
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA
| | - Eric Zoellner
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA
| | - Rama Ranganathan
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA
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2
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Hamley IW, Castelletto V. Small-angle scattering techniques for peptide and peptide hybrid nanostructures and peptide-based biomaterials. Adv Colloid Interface Sci 2023; 318:102959. [PMID: 37473606 DOI: 10.1016/j.cis.2023.102959] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/22/2023]
Abstract
The use of small-angle scattering (SAS) in the study of the self-assembly of peptides and peptide conjugates (lipopeptides, polymer-peptide conjugates and others) is reviewed, highlighting selected research that illustrates different methods and analysis techniques. Both small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS) are considered along with examples that exploit their unique capabilities. For SAXS, this includes the ability to perform rapid measurements enabling high throughput or fast kinetic studies and measurements under dilute conditions. For SANS, contrast variation using H2O/D2O mixtures enables the study of peptides interacting with lipids and TR-SANS (time-resolved SANS) studies of exchange kinetics and/or peptide-induced structural changes. Examples are provided of studies measuring form factors of different self-assembled structures (micelles, fibrils, nanotapes, nanotubes etc) as well as structure factors from ordered phases (lyotropic mesophases), peptide gels and hybrid materials such as membranes formed by mixing peptides with polysaccharides or peptide/liposome mixtures. SAXS/WAXS (WAXS: wide-angle x-ray scattering) on peptides and peptide hybrids is also discussed, and the review concludes with a perspective on potential future directions for research in the field.
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Affiliation(s)
- Ian W Hamley
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK.
| | - Valeria Castelletto
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK
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3
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Paquete-Ferreira J, Leisico F, Correia MAS, Engrola FSS, Santos-Silva T, Santos MFA. Using Small-angle X-ray Scattering to Characterize Biological Systems: A General Overview and Practical Tips. Methods Mol Biol 2023; 2652:381-403. [PMID: 37093488 DOI: 10.1007/978-1-0716-3147-8_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Small-angle X-ray Scattering (SAXS) is a versatile and powerful technique with applications in a wide range of fields. The continuous improvements in hardware, data analysis software, and standards for validation significantly contributed to increase its popularity and, nowadays, SAXS is a well-established method. SAXS allows to study flexible and dynamic systems (e.g., proteins and other biomolecules) in solution, providing information about their size and shape. Contrary to other structural characterization methods, SAXS has no limitations on the size of the particle under study and can be used in integrated approaches to reveal important insights otherwise difficult to obtain regarding folding-unfolding, conformational changes, movement of flexible regions, and the formation of complexes.This chapter, in addition to a concise overview on the methodology, intends to systematically enumerate the main steps involved in sample preparation and data collection, processing and analysis including useful practical notes to identify and overcome common bottlenecks. This way, a less experienced user can use the content of the chapter as a starting point to properly design and perform a successful SAXS experiment.
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Affiliation(s)
- João Paquete-Ferreira
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Francisco Leisico
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- Institut de Biologie Structurale, UMR 5075, University Grenoble Alpes, CNRS, CEA, Grenoble, France
| | - Márcia A S Correia
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Filipa S S Engrola
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Teresa Santos-Silva
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
| | - Marino F A Santos
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
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Schroen K, Berton-Carabin C, Renard D, Marquis M, Boire A, Cochereau R, Amine C, Marze S. Droplet Microfluidics for Food and Nutrition Applications. MICROMACHINES 2021; 12:863. [PMID: 34442486 PMCID: PMC8400250 DOI: 10.3390/mi12080863] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/15/2021] [Accepted: 07/19/2021] [Indexed: 01/05/2023]
Abstract
Droplet microfluidics revolutionizes the way experiments and analyses are conducted in many fields of science, based on decades of basic research. Applied sciences are also impacted, opening new perspectives on how we look at complex matter. In particular, food and nutritional sciences still have many research questions unsolved, and conventional laboratory methods are not always suitable to answer them. In this review, we present how microfluidics have been used in these fields to produce and investigate various droplet-based systems, namely simple and double emulsions, microgels, microparticles, and microcapsules with food-grade compositions. We show that droplet microfluidic devices enable unprecedented control over their production and properties, and can be integrated in lab-on-chip platforms for in situ and time-resolved analyses. This approach is illustrated for on-chip measurements of droplet interfacial properties, droplet-droplet coalescence, phase behavior of biopolymer mixtures, and reaction kinetics related to food digestion and nutrient absorption. As a perspective, we present promising developments in the adjacent fields of biochemistry and microbiology, as well as advanced microfluidics-analytical instrument coupling, all of which could be applied to solve research questions at the interface of food and nutritional sciences.
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Affiliation(s)
- Karin Schroen
- Food Process and Engineering Group, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands; (K.S.); (C.B.-C.)
| | - Claire Berton-Carabin
- Food Process and Engineering Group, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands; (K.S.); (C.B.-C.)
- INRAE, BIA Biopolymères Interactions Assemblages, F-44316 Nantes, France; (D.R.); (A.B.); (R.C.); (C.A.)
| | - Denis Renard
- INRAE, BIA Biopolymères Interactions Assemblages, F-44316 Nantes, France; (D.R.); (A.B.); (R.C.); (C.A.)
| | | | - Adeline Boire
- INRAE, BIA Biopolymères Interactions Assemblages, F-44316 Nantes, France; (D.R.); (A.B.); (R.C.); (C.A.)
| | - Rémy Cochereau
- INRAE, BIA Biopolymères Interactions Assemblages, F-44316 Nantes, France; (D.R.); (A.B.); (R.C.); (C.A.)
| | - Chloé Amine
- INRAE, BIA Biopolymères Interactions Assemblages, F-44316 Nantes, France; (D.R.); (A.B.); (R.C.); (C.A.)
| | - Sébastien Marze
- INRAE, BIA Biopolymères Interactions Assemblages, F-44316 Nantes, France; (D.R.); (A.B.); (R.C.); (C.A.)
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Kursula P. Small-angle X-ray scattering for the proteomics community: current overview and future potential. Expert Rev Proteomics 2021; 18:415-422. [PMID: 34210208 DOI: 10.1080/14789450.2021.1951242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Proteins are biological nanoparticles. For structural proteomics and hybrid structural biology, complementary methods are required that allow both high throughput and accurate automated data analysis. Small-angle X-ray scattering (SAXS) is a method for observing the size and shape of particles, such as proteins and complexes, in solution. SAXS data can be used to model both the structure, oligomeric state, conformational changes, and flexibility of biomolecular samples.Areas covered: The key principles of SAXS, its sample requirements, and its current and future applications for structural proteomics are briefly reviewed. Recent technical developments in SAXS experiments are discussed, and future potential of the method in structural proteomics is evaluated.Expert opinion: SAXS is a method suitable for several aspects of integrative structural proteomics, with current technical developments allowing for higher throughput and time-resolved studies, as well as the analysis of complex samples, such as membrane proteins. Increasing automation and streamlined data analysis are expected to equip SAXS for structure-based screening workflows. Originally, structural genomics had a heavy focus on folded, crystallizable proteins and complexes - SAXS is a method allowing an expansion of this focus to flexible and disordered systems.
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Affiliation(s)
- Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Biocenter Oulu & Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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6
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Lebedev DV, Egorov VV, Shvetsov AV, Zabrodskaya YA, Isaev-Ivanov VV, Konevega AL. Neutron Scattering Techniques and Complementary Methods for Structural and Functional Studies of Biological Macromolecules and Large Macromolecular Complexes. CRYSTALLOGR REP+ 2021. [DOI: 10.1134/s1063774521020103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract
The review describes the application of small-angle scattering (SAS) of neutrons and complementary methods to study the structures of biomacromolecules. Here we cover SAS techniques, such as the contrast variation, the neutron spin-echo, and the solution of direct and inverse problems of three-dimensional reconstruction of the structures of macromolecules from SAS spectra by means of molecular modeling. A special section is devoted to specific objects of research, such as supramolecular complexes, influenza virus nucleoprotein, and chromatin.
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Meisburger SP, Xu D, Ando N. REGALS: a general method to deconvolve X-ray scattering data from evolving mixtures. IUCRJ 2021; 8:225-237. [PMID: 33708400 PMCID: PMC7924237 DOI: 10.1107/s2052252521000555] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/14/2021] [Indexed: 06/10/2023]
Abstract
Mixtures of biological macromolecules are inherently difficult to study using structural methods, as increasing complexity presents new challenges for data analysis. Recently, there has been growing interest in studying evolving mixtures using small-angle X-ray scattering (SAXS) in conjunction with time-resolved, high-throughput or chromatography-coupled setups. Deconvolution and interpretation of the resulting datasets, however, are nontrivial when neither the scattering components nor the way in which they evolve are known a priori. To address this issue, the REGALS method (regularized alternating least squares) is introduced, which incorporates simple expectations about the data as prior knowledge, and utilizes parameterization and regularization to provide robust deconvolution solutions. The restraints used by REGALS are general properties such as smoothness of profiles and maximum dimensions of species, making it well suited for exploring datasets with unknown species. Here, REGALS is applied to the analysis of experimental data from four types of SAXS experiment: anion-exchange (AEX) coupled SAXS, ligand titration, time-resolved mixing and time-resolved temperature jump. Based on its performance with these challenging datasets, it is anticipated that REGALS will be a valuable addition to the SAXS analysis toolkit and enable new experiments. The software is implemented in both MATLAB and Python and is available freely as an open-source software package.
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Affiliation(s)
- Steve P. Meisburger
- Department of Chemistry and Chemical Biology, Cornell University, 259 East Avenue, Ithaca, NY 14853, USA
| | - Da Xu
- Department of Chemistry and Chemical Biology, Cornell University, 259 East Avenue, Ithaca, NY 14853, USA
| | - Nozomi Ando
- Department of Chemistry and Chemical Biology, Cornell University, 259 East Avenue, Ithaca, NY 14853, USA
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Cowieson NP, Edwards-Gayle CJC, Inoue K, Khunti NS, Doutch J, Williams E, Daniels S, Preece G, Krumpa NA, Sutter JP, Tully MD, Terrill NJ, Rambo RP. Beamline B21: high-throughput small-angle X-ray scattering at Diamond Light Source. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:1438-1446. [PMID: 32876621 PMCID: PMC7467336 DOI: 10.1107/s1600577520009960] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/20/2020] [Indexed: 05/06/2023]
Abstract
B21 is a small-angle X-ray scattering (SAXS) beamline with a bending magnet source in the 3 GeV storage ring at the Diamond Light Source Ltd synchrotron in the UK. The beamline utilizes a double multi-layer monochromator and a toroidal focusing optic to deliver 2 × 1012 photons per second to a 34 × 40 µm (FWHM) focal spot at the in-vacuum Eiger 4M (Dectris) detector. A high-performance liquid chromatography system and a liquid-handling robot make it possible to load solution samples into a temperature-controlled in-vacuum sample cell with a high level of automation. Alternatively, a range of viscous or solid materials may be loaded manually using a range of custom sample cells. A default scattering vector range from 0.0026 to 0.34 Å-1 and low instrument background make B21 convenient for measuring a wide range of biological macromolecules. The beamline has run a full user programme since 2013.
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Affiliation(s)
- Nathan P. Cowieson
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | | | - Katsuaki Inoue
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Nikul S. Khunti
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - James Doutch
- ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Eugene Williams
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Steven Daniels
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Geoff Preece
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Nicholas A. Krumpa
- Projects and Mechanical Engineering Group, Science and Technology Facilities Council, Daresbury Laboratory, Warrington, Cheshire WA4 4AD, United Kingdom
| | - John P. Sutter
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Mark D. Tully
- BM29 BIOSAXS, European Synchroton Radiation Facility, 71 avenue des Martyrs, Grenoble, Isère 38043, France
| | - Nick J. Terrill
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Robert P. Rambo
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
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Brosey CA, Tainer JA. Evolving SAXS versatility: solution X-ray scattering for macromolecular architecture, functional landscapes, and integrative structural biology. Curr Opin Struct Biol 2019; 58:197-213. [PMID: 31204190 PMCID: PMC6778498 DOI: 10.1016/j.sbi.2019.04.004] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 11/27/2022]
Abstract
Small-angle X-ray scattering (SAXS) has emerged as an enabling integrative technique for comprehensive analyses of macromolecular structures and interactions in solution. Over the past two decades, SAXS has become a mainstay of the structural biologist's toolbox, supplying multiplexed measurements of molecular shape and dynamics that unveil biological function. Here, we discuss evolving SAXS theory, methods, and applications that extend the field of small-angle scattering beyond simple shape characterization. SAXS, coupled with size-exclusion chromatography (SEC-SAXS) and time-resolved (TR-SAXS) methods, is now providing high-resolution insight into macromolecular flexibility and ensembles, delineating biophysical landscapes, and facilitating high-throughput library screening to assess macromolecular properties and to create opportunities for drug discovery. Looking forward, we consider SAXS in the integrative era of hybrid structural biology methods, its potential for illuminating cellular supramolecular and mesoscale structures, and its capacity to complement high-throughput bioinformatics sequencing data. As advances in the field continue, we look forward to proliferating uses of SAXS based upon its abilities to robustly produce mechanistic insights for biology and medicine.
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Affiliation(s)
- Chris A Brosey
- Molecular and Cellular Oncology and Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
| | - John A Tainer
- Molecular and Cellular Oncology and Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA; MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Abstract
AbstractThe dynamics of proteins in solution includes a variety of processes, such as backbone and side-chain fluctuations, interdomain motions, as well as global rotational and translational (i.e. center of mass) diffusion. Since protein dynamics is related to protein function and essential transport processes, a detailed mechanistic understanding and monitoring of protein dynamics in solution is highly desirable. The hierarchical character of protein dynamics requires experimental tools addressing a broad range of time- and length scales. We discuss how different techniques contribute to a comprehensive picture of protein dynamics, and focus in particular on results from neutron spectroscopy. We outline the underlying principles and review available instrumentation as well as related analysis frameworks.
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Järvå M, Phan TK, Lay FT, Caria S, Kvansakul M, Hulett MD. Human β-defensin 2 kills Candida albicans through phosphatidylinositol 4,5-bisphosphate-mediated membrane permeabilization. SCIENCE ADVANCES 2018; 4:eaat0979. [PMID: 30050988 PMCID: PMC6059731 DOI: 10.1126/sciadv.aat0979] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Human defensins belong to a subfamily of the cationic antimicrobial peptides and act as a first line of defense against invading microbes. Their often broad-spectrum antimicrobial and antitumor activities make them attractive for therapeutic development; however, their precise molecular mechanism(s) of action remains to be defined. We show that human β-defensin 2 (HBD-2) permeabilizes Candida albicans cell membranes via a mechanism targeting the plasma membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2). We determined the structure of HBD-2 bound to PIP2, which revealed two distinct PIP2-binding sites, and showed, using functional assays, that mutations in these sites ablate PIP2-mediated fungal growth inhibition by HBD-2. Our study provides the first insight into lipid-mediated human defensin membrane permeabilization at an atomic level and reveals a unique mode of lipid engagement to permeabilize cell membranes.
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Affiliation(s)
- Michael Järvå
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Thanh Kha Phan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Fung T Lay
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Sofia Caria
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
- SAXS/WAXS Beamline, Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Marc Kvansakul
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Mark D Hulett
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
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12
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Banjara S, Mao J, Ryan TM, Caria S, Kvansakul M. Grouper iridovirus GIV66 is a Bcl-2 protein that inhibits apoptosis by exclusively sequestering Bim. J Biol Chem 2018; 293:5464-5477. [PMID: 29483196 DOI: 10.1074/jbc.ra117.000591] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 02/21/2018] [Indexed: 11/06/2022] Open
Abstract
Programmed cell death or apoptosis is a critical mechanism for the controlled removal of damaged or infected cells, and proteins of the Bcl-2 family are important arbiters of this process. Viruses have been shown to encode functional and structural homologs of Bcl-2 to counter premature host-cell apoptosis and ensure viral proliferation or survival. Grouper iridovirus (GIV) is a large DNA virus belonging to the Iridoviridae family and harbors GIV66, a putative Bcl-2-like protein and mitochondrially localized apoptosis inhibitor. However, the molecular and structural basis of GIV66-mediated apoptosis inhibition is currently not understood. To gain insight into GIV66's mechanism of action, we systematically evaluated its ability to bind peptides spanning the BH3 domain of pro-apoptotic Bcl-2 family members. Our results revealed that GIV66 harbors an unusually high level of specificity for pro-apoptotic Bcl-2 and displays affinity only for Bcl-2-like 11 (Bcl2L11 or Bim). Using crystal structures of both apo-GIV66 and GIV66 bound to the BH3 domain from Bim, we unexpectedly found that GIV66 forms dimers via an interface that results in occluded access to the canonical Bcl-2 ligand-binding groove, which breaks apart upon Bim binding. This observation suggests that GIV66 dimerization may affect GIV66's ability to bind host pro-death Bcl-2 proteins and enables highly targeted virus-directed suppression of host apoptosis signaling. Our findings provide a mechanistic understanding for the potent anti-apoptotic activity of GIV66 by identifying it as the first single-specificity, pro-survival Bcl-2 protein and identifying a pivotal role of Bim in GIV-mediated inhibition of apoptosis.
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Affiliation(s)
- Suresh Banjara
- From the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia and
| | - Jiahao Mao
- From the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia and
| | - Timothy M Ryan
- SAXS/WAXS, Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Sofia Caria
- From the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia and
| | - Marc Kvansakul
- From the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia and
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Tuukkanen AT, Spilotros A, Svergun DI. Progress in small-angle scattering from biological solutions at high-brilliance synchrotrons. IUCRJ 2017; 4:518-528. [PMID: 28989709 PMCID: PMC5619845 DOI: 10.1107/s2052252517008740] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/12/2017] [Indexed: 05/26/2023]
Abstract
Small-angle X-ray scattering (SAXS) is an established technique that provides low-resolution structural information on macromolecular solutions. Recent decades have witnessed significant progress in both experimental facilities and in novel data-analysis approaches, making SAXS a mainstream method for structural biology. The technique is routinely applied to directly reconstruct low-resolution shapes of proteins and to generate atomistic models of macromolecular assemblies using hybrid approaches. Very importantly, SAXS is capable of yielding structural information on systems with size and conformational polydispersity, including highly flexible objects. In addition, utilizing high-flux synchrotron facilities, time-resolved SAXS allows analysis of kinetic processes over time ranges from microseconds to hours. Dedicated bioSAXS beamlines now offer fully automated data-collection and analysis pipelines, where analysis and modelling is conducted on the fly. This enables SAXS to be employed as a high-throughput method to rapidly screen various sample conditions and additives. The growing SAXS user community is supported by developments in data and model archiving and quality criteria. This review illustrates the latest developments in SAXS, in particular highlighting time-resolved applications aimed at flexible and evolving systems.
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Affiliation(s)
- Anne T. Tuukkanen
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Alessandro Spilotros
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
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Anasir MI, Caria S, Skinner MA, Kvansakul M. Structural basis of apoptosis inhibition by the fowlpox virus protein FPV039. J Biol Chem 2017; 292:9010-9021. [PMID: 28411240 DOI: 10.1074/jbc.m116.768879] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 04/13/2017] [Indexed: 11/06/2022] Open
Abstract
Programmed cell death or apoptosis of infected host cells is an important defense mechanism in response to viral infections. This process is regulated by proapoptotic and prosurvival members of the B-cell lymphoma 2 (Bcl-2) protein family. To counter premature death of a virus-infected cell, poxviruses use a range of different molecular strategies including the mimicry of prosurvival Bcl-2 proteins. One such viral prosurvival protein is the fowlpox virus protein FPV039, which is a potent apoptosis inhibitor, but the precise molecular mechanism by which FPV039 inhibits apoptosis is unknown. To understand how fowlpox virus inhibits apoptosis, we examined FPV039 using isothermal titration calorimetry, small-angle X-ray scattering, and X-ray crystallography. Here, we report that the fowlpox virus prosurvival protein FPV039 promiscuously binds to cellular proapoptotic Bcl-2 and engages all major proapoptotic Bcl-2 proteins. Unlike other identified viral Bcl-2 proteins to date, FPV039 engaged with cellular proapoptotic Bcl-2 with affinities comparable with those of Bcl-2's endogenous cellular counterparts. Structural studies revealed that FPV039 adopts the conserved Bcl-2 fold observed in cellular prosurvival Bcl-2 proteins and closely mimics the structure of the prosurvival Bcl-2 family protein Mcl-1. Our findings suggest that FPV039 is a pan-Bcl-2 protein inhibitor that can engage all host BH3-only proteins, as well as Bcl-2-associated X, apoptosis regulator (Bax) and Bcl-2 antagonist/killer (Bak) proteins to inhibit premature apoptosis of an infected host cell. This work therefore provides a mechanistic platform to better understand FPV039-mediated apoptosis inhibition.
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Affiliation(s)
- Mohd Ishtiaq Anasir
- From the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia and
| | - Sofia Caria
- From the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia and
| | - Michael A Skinner
- Section of Virology, Faculty of Medicine, Imperial College London, London W2 1PZ, United Kingdom
| | - Marc Kvansakul
- From the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia and
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15
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Sysoeva TA. Assessing heterogeneity in oligomeric AAA+ machines. Cell Mol Life Sci 2017; 74:1001-1018. [PMID: 27669691 PMCID: PMC11107579 DOI: 10.1007/s00018-016-2374-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 09/13/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022]
Abstract
ATPases Associated with various cellular Activities (AAA+ ATPases) are molecular motors that use the energy of ATP binding and hydrolysis to remodel their target macromolecules. The majority of these ATPases form ring-shaped hexamers in which the active sites are located at the interfaces between neighboring subunits. Structural changes initiate in an active site and propagate to distant motor parts that interface and reshape the target macromolecules, thereby performing mechanical work. During the functioning cycle, the AAA+ motor transits through multiple distinct states. Ring architecture and placement of the catalytic sites at the intersubunit interfaces allow for a unique level of coordination among subunits of the motor. This in turn results in conformational differences among subunits and overall asymmetry of the motor ring as it functions. To date, a large amount of structural information has been gathered for different AAA+ motors, but even for the most characterized of them only a few structural states are known and the full mechanistic cycle cannot be yet reconstructed. Therefore, the first part of this work will provide a broad overview of what arrangements of AAA+ subunits have been structurally observed focusing on diversity of ATPase oligomeric ensembles and heterogeneity within the ensembles. The second part of this review will concentrate on methods that assess structural and functional heterogeneity among subunits of AAA+ motors, thus bringing us closer to understanding the mechanism of these fascinating molecular motors.
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Affiliation(s)
- Tatyana A Sysoeva
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
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16
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Ibrahim Z, Martel A, Moulin M, Kim HS, Härtlein M, Franzetti B, Gabel F. Time-resolved neutron scattering provides new insight into protein substrate processing by a AAA+ unfoldase. Sci Rep 2017; 7:40948. [PMID: 28102317 PMCID: PMC5244417 DOI: 10.1038/srep40948] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 12/12/2016] [Indexed: 01/24/2023] Open
Abstract
We present a combination of small-angle neutron scattering, deuterium labelling and contrast variation, temperature activation and fluorescence spectroscopy as a novel approach to obtain time-resolved, structural data individually from macromolecular complexes and their substrates during active biochemical reactions. The approach allowed us to monitor the mechanical unfolding of a green fluorescent protein model substrate by the archaeal AAA+ PAN unfoldase on the sub-minute time scale. Concomitant with the unfolding of its substrate, the PAN complex underwent an energy-dependent transition from a relaxed to a contracted conformation, followed by a slower expansion to its initial state at the end of the reaction. The results support a model in which AAA ATPases unfold their substrates in a reversible power stroke mechanism involving several subunits and demonstrate the general utility of this time-resolved approach for studying the structural molecular kinetics of multiple protein remodelling complexes and their substrates on the sub-minute time scale.
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Affiliation(s)
- Ziad Ibrahim
- Université Grenoble Alpes, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre National de la Recherche Scientifique, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Structurale, 38044 Grenoble, France.,Institut Laue-Langevin, 38042 Grenoble, France
| | - Anne Martel
- Institut Laue-Langevin, 38042 Grenoble, France
| | | | - Henry S Kim
- Université Grenoble Alpes, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre National de la Recherche Scientifique, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Structurale, 38044 Grenoble, France
| | | | - Bruno Franzetti
- Université Grenoble Alpes, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre National de la Recherche Scientifique, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Structurale, 38044 Grenoble, France
| | - Frank Gabel
- Université Grenoble Alpes, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre National de la Recherche Scientifique, Institut de Biologie Structurale, 38044 Grenoble, France.,Centre à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Structurale, 38044 Grenoble, France.,Institut Laue-Langevin, 38042 Grenoble, France
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17
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Brookes E, Vachette P, Rocco M, Pérez J. US-SOMO HPLC-SAXS module: dealing with capillary fouling and extraction of pure component patterns from poorly resolved SEC-SAXS data. J Appl Crystallogr 2016; 49:1827-1841. [PMID: 27738419 PMCID: PMC5045733 DOI: 10.1107/s1600576716011201] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 07/10/2016] [Indexed: 11/23/2022] Open
Abstract
The US-SOMO HPLC-SAXS (high-performance liquid chromatography coupled with small-angle X-ray scattering) module is an advanced tool for the comprehensive analysis of SEC-SAXS (size-exclusion chromatography coupled with SAXS) data. It includes baseline and band-broadening correction routines, and Gaussian decomposition of overlapping skewed peaks into pure components. Size-exclusion chromatography coupled with SAXS (small-angle X-ray scattering), often performed using a flow-through capillary, should allow direct collection of monodisperse sample data. However, capillary fouling issues and non-baseline-resolved peaks can hamper its efficacy. The UltraScan solution modeler (US-SOMO) HPLC-SAXS (high-performance liquid chromatography coupled with SAXS) module provides a comprehensive framework to analyze such data, starting with a simple linear baseline correction and symmetrical Gaussian decomposition tools [Brookes, Pérez, Cardinali, Profumo, Vachette & Rocco (2013 ▸). J. Appl. Cryst.46, 1823–1833]. In addition to several new features, substantial improvements to both routines have now been implemented, comprising the evaluation of outcomes by advanced statistical tools. The novel integral baseline-correction procedure is based on the more sound assumption that the effect of capillary fouling on scattering increases monotonically with the intensity scattered by the material within the X-ray beam. Overlapping peaks, often skewed because of sample interaction with the column matrix, can now be accurately decomposed using non-symmetrical modified Gaussian functions. As an example, the case of a polydisperse solution of aldolase is analyzed: from heavily convoluted peaks, individual SAXS profiles of tetramers, octamers and dodecamers are extracted and reliably modeled.
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Affiliation(s)
- Emre Brookes
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3901, USA
| | - Patrice Vachette
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, F-91198, France
| | - Mattia Rocco
- Biopolimeri e Proteomica, IRCCS AOU San Martino-IST, Istituto Nazionale per la Ricerca sul Cancro, Largo R. Benzi 10, Genova, I-16132, Italy
| | - Javier Pérez
- SWING Beamline, Synchrotron SOLEIL, L'Orme des Merisiers, BP48, Saint-Aubin, Gif-sur-Yvette, F-91192, France
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18
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Vestergaard B. Analysis of biostructural changes, dynamics, and interactions – Small-angle X-ray scattering to the rescue. Arch Biochem Biophys 2016; 602:69-79. [DOI: 10.1016/j.abb.2016.02.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/17/2016] [Accepted: 02/26/2016] [Indexed: 12/27/2022]
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19
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Caria S, Marshall B, Burton RL, Campbell S, Pantaki-Eimany D, Hawkins CJ, Barry M, Kvansakul M. The N Terminus of the Vaccinia Virus Protein F1L Is an Intrinsically Unstructured Region That Is Not Involved in Apoptosis Regulation. J Biol Chem 2016; 291:14600-8. [PMID: 27151220 DOI: 10.1074/jbc.m116.726851] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Indexed: 12/21/2022] Open
Abstract
Subversion of host cell apoptotic responses is a prominent feature of viral immune evasion strategies to prevent premature clearance of infected cells. Numerous poxviruses encode structural and functional homologs of the Bcl-2 family of proteins, and vaccinia virus harbors antiapoptotic F1L that potently inhibits the mitochondrial apoptotic checkpoint. Recently F1L has been assigned a caspase-9 inhibitory function attributed to an N-terminal α helical region of F1L spanning residues 1-15 (1) preceding the domain-swapped Bcl-2-like domains. Using a reconstituted caspase inhibition assay in yeast we found that unlike AcP35, a well characterized caspase-9 inhibitor from the insect virus Autographa californica multiple nucleopolyhedrovirus, F1L does not prevent caspase-9-mediated yeast cell death. Furthermore, we found that deletion of the F1L N-terminal region does not impede F1L antiapoptotic activity in the context of a viral infection. Solution analysis of the F1L N-terminal regions using small angle x-ray scattering indicates that the region of F1L spanning residues 1-50 located N-terminally from the Bcl-2 fold is an intrinsically unstructured region. We conclude that the N terminus of F1L is not involved in apoptosis inhibition and may act as a regulatory element in other signaling pathways in a manner reminiscent of other unstructured regulatory elements commonly found in mammalian prosurvival Bcl-2 members including Bcl-xL and Mcl-1.
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Affiliation(s)
- Sofia Caria
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Bevan Marshall
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Robyn-Lee Burton
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Stephanie Campbell
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Delara Pantaki-Eimany
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Christine J Hawkins
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Michele Barry
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Marc Kvansakul
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
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20
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Burton DR, Caria S, Marshall B, Barry M, Kvansakul M. Structural basis of Deerpox virus-mediated inhibition of apoptosis. ACTA ACUST UNITED AC 2015; 71:1593-603. [PMID: 26249341 DOI: 10.1107/s1399004715009402] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 05/18/2015] [Indexed: 01/21/2023]
Abstract
Apoptosis is a key innate defence mechanism to eliminate virally infected cells. To counteract premature host-cell apoptosis, poxviruses have evolved numerous molecular strategies, including the use of Bcl-2 proteins, to ensure their own survival. Here, it is reported that the Deerpox virus inhibitor of apoptosis, DPV022, only engages a highly restricted set of death-inducing Bcl-2 proteins, including Bim, Bax and Bak, with modest affinities. Structural analysis reveals that DPV022 adopts a Bcl-2 fold with a dimeric domain-swapped topology and binds pro-death Bcl-2 proteins via two conserved ligand-binding grooves found on opposite sides of the dimer. Structures of DPV022 bound to Bim, Bak and Bax BH3 domains reveal that a partial obstruction of the binding groove is likely to be responsible for the modest affinities of DPV022 for BH3 domains. These findings reveal that domain-swapped dimeric Bcl-2 folds are not unusual and may be found more widely in viruses. Furthermore, the modest affinities of DPV022 for pro-death Bcl-2 proteins suggest that two distinct classes of anti-apoptotic viral Bcl-2 proteins exist: those that are monomeric and tightly bind a range of death-inducing Bcl-2 proteins, and others such as DPV022 that are dimeric and only bind a very limited number of death-inducing Bcl-2 proteins with modest affinities.
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Affiliation(s)
- Denis R Burton
- Department of Biochemistry, La Trobe University, Melbourne, VIC 3058, Australia
| | - Sofia Caria
- Department of Biochemistry, La Trobe University, Melbourne, VIC 3058, Australia
| | - Bevan Marshall
- Department of Biochemistry, La Trobe University, Melbourne, VIC 3058, Australia
| | - Michele Barry
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Marc Kvansakul
- Department of Biochemistry, La Trobe University, Melbourne, VIC 3058, Australia
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21
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Boldon L, Laliberte F, Liu L. Review of the fundamental theories behind small angle X-ray scattering, molecular dynamics simulations, and relevant integrated application. NANO REVIEWS 2015; 6:25661. [PMID: 25721341 PMCID: PMC4342503 DOI: 10.3402/nano.v6.25661] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 11/24/2014] [Accepted: 01/18/2015] [Indexed: 12/16/2022]
Abstract
In this paper, the fundamental concepts and equations necessary for performing small angle X-ray scattering (SAXS) experiments, molecular dynamics (MD) simulations, and MD-SAXS analyses were reviewed. Furthermore, several key biological and non-biological applications for SAXS, MD, and MD-SAXS are presented in this review; however, this article does not cover all possible applications. SAXS is an experimental technique used for the analysis of a wide variety of biological and non-biological structures. SAXS utilizes spherical averaging to produce one- or two-dimensional intensity profiles, from which structural data may be extracted. MD simulation is a computer simulation technique that is used to model complex biological and non-biological systems at the atomic level. MD simulations apply classical Newtonian mechanics' equations of motion to perform force calculations and to predict the theoretical physical properties of the system. This review presents several applications that highlight the ability of both SAXS and MD to study protein folding and function in addition to non-biological applications, such as the study of mechanical, electrical, and structural properties of non-biological nanoparticles. Lastly, the potential benefits of combining SAXS and MD simulations for the study of both biological and non-biological systems are demonstrated through the presentation of several examples that combine the two techniques.
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Affiliation(s)
- Lauren Boldon
- Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA;
| | - Fallon Laliberte
- Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Li Liu
- Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA;
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